The objective of this program is the development of a new small vessel prosthesis for vascular reconstructive surgery. The new prosthesis is made entirely from silicone rubber, a stable material in vivo. It employs a textured surface at the blood interface to promote the deposition of a pseudoneointima (PNI) for blood compatibility, a solid wall to obtain a desired radial compliance and isolate the graft interior from external tissues and fluids, and an exterior textured surface to promote tissue attachment to the prosthesis to minimize compliance loss following healing of the perigraft tissues. To evaluate its performance in detail, a series of experiments will be conducted using the canine carotid artery model in which the compliance of the graft will be monitored noninvasively over a six month period using pulsed ultrasound echo-tracking; and the composition and structure of the graft PNI will be examined using immunohistochemical methods. To determine the optimum duration for using platelet inhibitors with this graft design, the uptake of radiolabelled platelets by the PNI will be measured as a function of time. Specifically for its relevance to coronary bypass surgery, the performance of the graft implanted intrathoracically and with end-to-side anastomoses will be studied; and a series of experiments of 1 year duration are to be conducted to determine the long term patency rate of the new prosthesis in the canine model. As the performance of currently available small vessel prostheses is inadequate, the commercial potential of an improved prosthesis for peripheral vascular and coronary bypass surgery is significant.